Soluble coffee products, often referred to as “instant coffee,” are prepared from aqueous extracts of roasted and ground coffee. The products are generally in the form of spray-dried or freeze-dried particulate solids.
Traditionally, soluble coffee is made by the known art of percolation in which roast and ground coffee of a specific roast color for each product design is extracted using hot water to produce an aqueous coffee extract. Next, the aqueous coffee extract is typically immediately cooled upon exiting the percolator to less than 95° F. to maintain flavor integrity. The aqueous solution is then centrifuged to remove any extraneous insoluble solids. The solution or in some instances part of the solution is then evaporated at low temperatures under vacuum, typically no higher than 160° F., to remove water and aroma while maintaining flavor integrity. The resulting solution which can be from 20 to 58% soluble solids concentration is converted to a low moisture coffee powder using known art techniques of spray-drying or freeze-drying with aroma addback.
The flavor of the resulting coffee is controlled through bean blend, roast color of the roast, and ground and percolation conditions. However, the conventional perception of the in-cup flavor and associated strength is the brew color. Darker roasted coffees taste substantially different than lighter roasted coffees and the in-cup brew color of a darker roasted coffee is substantially darker than the brew colors of light roasted coffees.
In the soluble coffee art there has been minimal emphasis in trying to achieve a dark espresso type cup of coffee without the burnt flavor notes that typically accompany dark roasts. The conventional methods of producing soluble coffee are focused on flavor quality, yield, efficiency, product powder color, powder density and fines. The in-cup brew color (i.e., the color of re-constituted soluble coffee) is typically accepted to be a function of the roast color of the roast and ground coffee from which the soluble coffee was produced.
One conventional method of manipulating the brew color of 100% pure coffee products is provided via the roast color of the coffee beans prior to percolation. However, this conventional method also has the consequence of altering the flavor of the resulting coffee to a certain extent depending on the degree of roast.
For example, U.S. Pat. No. 6,120,831 to Zeller, et al., herein incorporated by reference, discloses a method of increasing the flavor and color of soluble coffee by heating the soluble coffee at a temperature and for a time sufficient to intensify the flavor and color of the coffee without causing carbohydrate pyrolysis.
Another previous method for increasing the in-cup brew color is provided U.S. Pat. No. 6,399,131 entitled “Soluble coffee having intensified flavor and color and method of making the same from a coffee extract,” herein incorporated by reference. In the U.S. Pat. No. 6,399,131 method, the coffee extract is heated to a desired temperature for a desired time to intensify both the color and flavor of the coffee extract. As a result, the U.S. Pat. No. 6,399,131 method produces a soluble coffee extract, and subsequent in-cup brew coffee, with intensified color and flavor as compared with soluble coffee not subjected to its intensification method. However, this process affects both color and flavor and therefore, the color cannot be changed without affecting the flavor of the coffee.
Thus, the prior art, e.g. U.S. Pat. No. 6,120,831 and U.S. Pat. No. 6,399,131, teaches that manipulating the brew color through heating the coffee extract necessarily affects the resulting coffee flavor.
There is a need in the art to have a method of increasing in-cup brew color of a soluble coffee extract without affecting (i.e. altering) the flavor coffee extract or the flavor of the coffee after reconstitution of the soluble coffee extract.